where the maximization is over all POVMs \(\Pi _{\mathcal {F}}\)  and \(f\)  labels the
outcomes of \(\Pi _{\mathcal {F}}\)  and \(p_{f}\)  their probabilities. In that work,
they compute the quantum mutual information, the Holevo quantity in
Eq. (REF ), and the alternative Holevo quantity in Eq.
(REF ) for a “c-maybe” model of decoherence
of \(\mathcal {S}\)  by \(\mathcal {E}\) , a model that falls into the class of purely decohering
models (see below). They analytically found \(\chi \left(\mathcal {S}:\check{\mathcal {F}}\right)\) 
by making use of the Koashi-Winter monogamy relation [1]}
and showed all the mutual information quantities above approach the
missing information, \(H_{\mathcal {S}}\) , with a similar dependence on \(\mathcal {F}\) .
